VTNET_MAXSEGS
struct virtio_mrg_rxbuf_info info[VTNET_MAXSEGS];
struct iovec iov[VTNET_MAXSEGS + 1];
int n = vq_getchain(vq, riov, VTNET_MAXSEGS - riov_len,
assert(n >= 1 && riov_len + n <= VTNET_MAXSEGS);
} while (riov_bytes < plen && riov_len < VTNET_MAXSEGS);
struct iovec iov[VTNET_MAXSEGS + 1];
n = vq_getchain(vq, iov, VTNET_MAXSEGS, &req);
assert(n >= 1 && n <= VTNET_MAXSEGS);